Calcification of glutaraldehyde-preserved or “fixed” bioprosthetic heart valves frequently occurs and leads to failure due to stenosis and regurgitation. In addition, the slow release of glutaraldehyde from the implanted device is cytotoxic. Several methods of tissue cross-linking or fixing that are independent of glutaraldehyde have been presented, and they include acyl azide, photooxidation, epoxy, genipin and carbodiimide. The latter is described in U.S. Pat. No. 5,733,339 issued Mar. 31, 1998. However, it is acknowledged that tissue shrinkage occurs during fixation, and no cross-linking method has yet been perfected that totally avoids tissue shrinkage (J. Heart Valve Dis. 2001; 10(1): 111-124). While this may be of no particular concern with respect to much pericardium or tissue for which tailoring will take place after fixation, it may well be an issue for porcine aortic root leaflets where precise interengagement, i.e. coaptation, is very important and excessive shrinkage may induce insufficient coaptation of the cusps which could render the valve incompetent. Therefore, the need for improved fixation technology that induces only minimum tissue shrinkage still exists, and the search for such technology has continued.